evince no longer renders grayscale DjVu docs

[Bill Yikes]

Evince used to have no problem showing a grayscale djvu file. Version 3.22.1 was fine. Now evince version 3.38.2 presents an error: 'Unable to open document "grayscale_sample.djvu". File type DjVu image (image/gnd.djvu) is not supported.' Now evince can only render bilevel DjVu images.

To reproduce, start with a grayscale *.pgm file. Use ImageMagick if needed to obtain one, as follows:

$ convert logo: sample_grayscale.pgm

Convert to djvu:

$ c44 sample_grayscale.pgm sample_grayscale.djvu

Finally:

$ evince sample_grayscale.djvu

(broken)